The present invention is directed to various forms of seat assemblies and is particularly concerned with structural arrangements which enable a simple and rapid assembly of an upholstered seat back to an upholstered seat base. Although well-adapted for use in other applications, the seat assemblies of the present invention find a primary application in the assembly of automotive vehicle seats in a production line setting.
Automotive seat assemblies normally are produced by fabricating the seat base and seat back independently from each other and assembling these two components to each other only after the components are in their completed, upholstered state. As is invariably the case with automotive vehicle components, the final assembly process, in this case the attaching of the completed seat back to the completed seat base, is performed on a production line. The attachment devices employed to attach the seat back to its base must be capable of being coupled tightly to each other in a minimum amount of time in a positive locking inter-engagement with each other which will remain interlocked in the face of vibration and shock loading, including crash loading. The devices must be made up of individual parts which can be cheaply and rapidly produced on a mass production basis. In that most present-day front seats in automobiles have provisions for tilting the back relative to the seat base, either to provide access to the rear seat of a two-door vehicle or to enable the seat back to be reclined, the attachment device should be equally well-adapted for use in mounting a tilting seat back on the base or alternatively being capable of attaching a seat back in a fixed position relative to the seat base.
This latter requirement is typically met by constructing the seat base with a rigid link-like coupling bar secured at its lower end to the seat base frame and projecting upwardly through the seat upholstery at each side of the rear portion of the seat base. The coupling bar may be pivoted at its lower end either directly or indirectly to the seat base frame or alternatively bolted or welded to the frame in those applications where tilting of the seat back is not required. The coupling elements mounted on the seat back usually take the form of housings fixedly mounted to the seat back frame at either side of the bottom portion of the frame. Each housing is formed with a recess which receives a coupling bar and detents, spring-loaded latches or wedging arrangements are employed which accommodate movement of the seat back to its assembled position relative to the seat base and to grip or positively lock the seat back to the base once it arrives in its final assembled position. For examples of such devices, see U.S. Pat. Nos. 4,890,888 and 5,005,908.
One of the difficulties with prior art devices resides in the fact that for sake of appearances, the seat back and seat base attaching assemblies, once joined, find the seat base coupling member received within a housing or bracket concealed within the interior of the seat back. In that the device is deliberately designed so that the back and seat base will remain assembled to each other in crash or roll-over situations, disassembly of the seat back from the seat base is, in many cases, impossible without cutting through the upholstery to expose the coupling units and then attempting to separate the base attached link from the seat back attached housing, a procedure which usually involves some brute force application to components which are not conveniently accessible, particularly at the inner sides of the seats.
The present invention is especially directed to structural arrangements for mounting a seat back unit upon a seat base unit in a manner which enables a substantially fool-proof positive locking of the two units to each other by simple and rapidly performed assembly steps while also including provisions for disassembling the back from the base.